1. Field of the Invention
The invention relates generally to fuse structures within microelectronic structures. More particularly, the invention relates to enhanced performance fuse structures within microelectronic structures.
2. Description of the Related Art
In addition to transistors, resistors, capacitors and diodes, semiconductor structures and semiconductor circuits often include fuses. Fuses within semiconductor circuits are desirable insofar as fuses provide an efficient means for severing a portion of a semiconductor circuit that may be otherwise defective and unoperational. In particular, fuses are often useful in severing portions of memory array circuits that are otherwise defective and unoperational. Fuses may also be used to electrically trim various semiconductor circuit components, such as variable resistance semiconductor circuit components.
Although fuses are essential within semiconductor circuit fabrication, fuses are nonetheless not entirely without problems. In particular, while providing a means for severing portions of a semiconductor circuit that are defective and unoperational, fuses may not under all circumstances themselves operate efficiently absent defects. For example, in some instances fuses do not always readily program efficiently, particularly under circumstances where a programming current and/or a programming voltage is desired to be low. In some other instances, fuses that have apparently been programmed may nonetheless allow flow of an undesirably high, albeit reduced, current.
Fuses and fuse structures having desirable properties are known in the semiconductor fabrication art.
For example, Kikuchi et al., in U.S. Pat. No. 4,908,692, teaches a semiconductor device that includes a low resistance fuse with desirable programming properties. Within the semiconductor device, the low resistance fuse comprises a high melting point metal silicide material.
In addition, LaFleur et al., in U.S. Pat. No. 5,903,041, teaches an integrated fuse and antifuse structure with enhanced performance for use within a semiconductor structure. The integrated fuse and antifuse structure includes an air gap proximate to a fuse portion thereof.
Further, Arndt et al., in U.S. Pat. No. 6,274,440, teaches a fuse structure that may be fabricated with enhanced process efficiency within a semiconductor structure. The fuse structure includes a gate conductor stack that is located within a gap within the semiconductor structure.
Still further, Kothandaraman et al., in U.S. Pat. No. 6,624,499, teaches a system for programming a silicide fuse with enhanced efficiency within a semiconductor structure. To effect the enhanced efficiency, the system provides a temperature gradient to the silicide fuse when programming the silicide fuse.
Still yet further, Bertin et al., in U.S. Pat. No. 6,633,055 teaches a fuse that may be readily fabricated within a semiconductor structure. This particular fuse may be fabricated from a conductor layer within the semiconductor structure, to provide the fuse that is proximate with a gap.
Still yet further, Anderson et al., in U.S. Pat. No. 6,972,472, teaches yet another fuse structure that may be fabricated within a semiconductor structure. This particular fuse structure includes a fuse element that rises above an insulator layer and is separated from the insulator layer by a gap.
Finally, Kothandaraman et al., in U.S. Pat. No. 7,242,072, teaches yet another fuse structure that may be fabricated within a semiconductor structure. This particular fuse structure uses a crystalline semiconductor layer as a fuse layer substrate.
Since fuses and fuse structures are likely to be of considerable continued importance as semiconductor technology advances, desirable are fuses and fuse structures with enhanced performance for use within semiconductor structures. Such enhanced performance is particularly desired under circumstances where a low fuse programming current is desired.